1. Field of the Invention
The present invention relates to a light source apparatus, and specifically relates to a light source apparatus enabling normal observation and special light observation to be performed simultaneously.
2. Description of the Related Art
Conventionally, light source apparatuses enabling special light observation such as narrow band observation (narrow band imaging: NBI) that enables observation of a site in the vicinity of a superficial portion of the mucous membrane of a living tissue in addition to normal observation (white light imaging: WLI) using white illumination have been developed (see, for example, Japanese Patent Laid-Open No. 2006-75239).
Such light source apparatuses include a turret including a plurality of optical filters, and mode switching between normal observation and special light observation is made by arranging an optical filter according to the observation mode in an optical path of a xenon lamp.
Furthermore, in recent years, with an increase in light amount of white LEDs, light source apparatuses using LEDs have been developed also in the field of endoscopes. Furthermore, in the field of endoscopes, there is a large demand for narrow band observation, and thus, light source apparatus configurations enabling narrow band observation using a white LED and a violet LED have been devised.
In such light source apparatuses, narrow band observation is performed by joining light from the violet LED to an optical path of the white LED using a dichroic filter that reflects a violet light band for narrow band observation. Then, the light source apparatuses are configured so as to insert/withdraw the dichroic filter to/from the optical path of the white LED according to the observation mode, whereby switching between normal observation and narrow band observation is made.